Identify difference in lighting between sheep it and local render in these two images
Doing a difference of the two images is a little more revealing: 

What do you notice? For one, the light fixtures themselves are black. And there are no reflections of lights, only of other objects.Further, the direct shine from a light is seen through the glass (center right), but nowhere else. My guess is something in the sheep-it version has more indirect light. I'm not sure WHY this is the case, (I would expect it to render the file as is) but it may be using more diffuse/glossy bounces, or have increased/disabled the threshold for the "clamp indirect" setting.